Q: Haileyesus asks, "How do you increase the size of a virtual hard disk?"
A: Unfortunately, Haileyesus, there's no way to increase the size of a virtual hard disk (VHD) once it's been created. VHDs are just like physical disks in this respect (and in most others, as well). If you need more space on your VHD, you'll need to create a new, larger .vhd file and then transfer your data to it. There are a couple of approaches you can take to transfer data, depending on whether the VHD contains a system partition. (Alternatively, you can attach an additional VHD to your virtual machine to add data storage capacity.)
1. If the VHD contains data with no operating system or installed applications, then you only need to copy the data to the new .vhd, as follows.
2. If the VHD includes an operating system and/or installed applications, you'll need to to this: